The results illustrated here were generated with a modified version
Subpixel Classifier. This software is not currently commercially
In response to a government request, IMAGINE
Subpixel Classifier was enhanced to detect multiple materials
simultaneously, unlike the commercial product that is used to search
for one material at a time. This modified software can be used to
categorize major terrain features for the purpose of landscape characterization
or habitat analysis. It identifies the principal scene materials
and the fraction of each material in each pixel.
Includes material © Space Imaging L.P.
This Quantitative Terrain Categorization is an unsupervised process.
The computer identifies spectral groups and labels them as land
or water. A human analyst can further label these output classes
if desired. Computer analysis is done on a subpixel level, so more
than one spectral class can be present in each pixel.
A separate image plane is generated for each of 16 spectral classes
so that the amount of each material can be quantified as occupying
a certain percent of the pixel. By combining these image planes,
the researcher can see relationships between classes. There is significantly
more information than in a traditional 16 class terrain categorization.
For example, one class may be identified as water while a second
class characterized as trees. If both classes appear in the same
pixel, as they may with this quantitative terrain categorizer, then
an analyst may assess the area as forested wetland, an environmental
unit not uniquely represented by the 16 spectral classes.
In the results illustrated here, the occurrences of six of the
sixteen spectral classes are shown (classes 1, 2, 3, 10, 12 and
13). An analyst using aerial photography of a few sites has labeled
class 12 as coniferous forest (green) and class 13 as deciduous
forest (red). Those areas shown in orange contain both class 12
and 13, a mixture of both coniferous and deciduous trees. This mixture
does not occur randomly throughout the scene, but rather indicates
particular ecological units.